Hydraulic weight control and compensating apparatus



Oct. 6, 1964 A. w. KAMMERER 3,151,686

HYDRAULIC WEIGHT CONTROL AND COMPENSATING APPARATUS Filed May 14, 1962 22 Pump I u Pass/val INVENTOR.

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United States Patent 3,151,686 HYDRAULEC WEIGHT CONTROL AND COMPENSATlN G AIPARATUS Archer W. Kammerer, 889 N. Raymond Ave, Fullerton,

Calif., assignor of one-fifth to Jean K. Lamphere, Fullerton, Calif., and one-fifth to Archer W. Kanimerer, In,

Houston, Tex.

Filed May 14, 1962, Ser. No. 194,499 8 Claims. (Cl. 175-5) The present invention relates to suspension apparatus used for supporting tubular strings, such as drill pipe, casing and tubing, in well bores.

In United States Patent No. 2,945,676, a hydraulic weight control and compensating apparatus is disclosed for maintaining the Weight imposed by a drilling string on a drill bit constant while a bore hole is being drilled. The apparatus is mounted in the rig between the traveling block and swivel, which is connected to the string of drill pipe, ad has various hydraulic lines and other equipment associated with it. All of this equipment s located within the working region of the derrick and is movable upwardly and downwardly with the traveling block and drill pipe, resulting in its exposure to contact with other parts of the rig, and diiferent tools and equipment, which might inflict damage upon it, or disrupt a hydraulic line, thereby rendering the apparatus inoperable.

Accordingly, it is an object of the present invention to provide hydraulic weight control and compensating apparatus located in a rig in such position that the risk of damage to the apparatus, including its hydraulic lines, is considerably minimized, if not eliminated entirely.

Another object of the invention is to provide hydraulic weight control and compensating apparatus that does not interfere with other equipment used in drilling a bore hole, or in performing other operations in the bore hole.

A further object of the invention is to provide hydraulic weight control and compensating apparatus adapted to form part of a rig mounted on a floating barge, which is capable of supporting a running-in string in a bore hole underlying a body of water and of maintaining the effective stress of the running-in string or equipment attached to it substantially constant, despite undulations of the barge in the water, the parts of the apparatus having a lesser extent of relative movement while the apparatus is performing its compensating function.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

FIGURE 1 is a diagrammatic view of a specific application of the invention;

FIG. 2 is a diagrammatic view of the weight control and compensating apparatus mounted at the upper portion of the derrick disclosed in FIG. 1.

A weight control and compensating apparatus A is disclosed in the drawings as being operatively associated with a rig used for drilling a well bore B, such as a well bore underlying a body of water W, the mouth of the well being at the floor F of the body of water. A floating barge C supports the rig, this floating barge having a suitable derrick D mounted thereon in which is contained the usual crown block E over and through which passes a EJElfidh Patented Get. 6, 1964 suitable member of cables or lines L that pass over the sheaves of a traveling block T, the hook H of which is connected to a swivel S secured to the upper kelly portion K of a string of drill pipe M extending through the body of water and into the bore hole B, the drill pipe having a suitable drill bit R on its lower end for drilling the hole. Suitable drilling fluid is pumped through a mud line V into the swivel S for downward passage through the drill pipe M and for discharge from the drill bit, the drilling fluid carrying the cuttings upwardly of the hole B and around the drill pipe to the fioor of the ocean for suitable disposal. The string of drill pipe M and the bit R are rotated in the usual manner by a rotary table W through which the kelly K is slidably splined, the cables or lines L passing over the crown block E and to a suitable drawworks P mounted on the floating barge C.

The weight control and compensating apparatus A is disposed completely out of the normal working area within the confines of a derrick I), being mounted on the upper end of the derrick. It includes a stationary cylinder 10 suitably fixed to and supported by the upper portion of the derrick, this cylinder having a suitable length, which may, for example, be about ten feet. It has an upper cylinder head 11 provided with a vent hole 12 to allow the upper portion of the cylinder to be at atmospheric pressure. A piston 13 is slidably mounted in this cylinder and has a piston rod 14 secured thereto passing through a lower cylinder head 15. The piston rod 14 may have a length corresponding to the length of the cylinder 18 and is suitably connected to the crown block E, as by providing an eye 16 in the lower end of the piston rod which receives a hook 17 secured to the crown block.

The cylinder 1% below the piston 13 is adapted to contain a body of liquid 18, such as oil, leakage of fluid downwardly from the cylinder along the piston rod 14 being prevented by a suitabl rod packing 19 mounted in the lower cylinder head 15 and slidably and sealingly engaging the piston rod; whereas, leakage of fluid upwardly past the piston 13 is prevented by a suitable seal ring 29 mounted in a peripheral groove 21 in the piston and slidably and sealingly engaging the wall of the cylinder 16.

The liquid 18 in the cylinder is maintained at substantially a constant pressure, this liquid being derived from a suitable reservoir 22, which may be located outside the working area within the derrick, a motor driven pump 23 drawing the oil from the reservoir 22 and discharging it through an inlet line 24 into the lower end of the cylinder It). The liquid in the cylinder can pass outwardly therefrom through an outlet line 25 and back to the reservoir 22, flowing through a suitable choke orifice 26 in the outlet line. The motor driven pump 23 may be a centrifugal pump capable of developing comparatively high pressures, this pump constantly rotating during the op eration of the apparatus and constantly delivering liquid into the cylinder 19 below the piston 13, the liquid c0'n stantly flowing through the outlet line 25 and the choke orifice 26 back to the reservoir 22. Because of the choke orifice 2s, a back pressure is built up in the cylinder 1t and inlet line 24, and in that portion of the outlet line 25 upstream of the choke orifice 26, which pressure acts upon the underside of the piston 13 and exerts an upward force thereon, which upward force is transmitted through the piston rod 14 to the movable crown block E, and through the lines L passing over the crown block to the traveling block T and the swivel S, which is connected to the drill pipe M.

The weight of the strin of drill pipe M and or" the mechanism cormected thereto is known by securing an indication on a suitable weight indicator (not shown). This weight is counteracted by the pressure or" the liquid acting upwardly over the effective cross-sectional area of the piston 13 outwmdly of the piston rod. The weight of the mechanism suspended from the piston 13, including the string of drill pipe M, less the total force of liquid acting upwardly on the piston, will provide the net downweight acting on the drill bit R and forcing it against the bottom of the bore hole B. By changing the pressure of the liquid 13, the drilling weight on the bit can be changed correspondingly. The pressure of the liquid is known to the o erator, as by observing a suitable pressure gauge 28 connected to the inlet line 24.

The hydraulic lines 24, 25 may extend suitably from the lower end of the cylinder 19. Preferably, they will run downwardly along the exterior of the derrick D, out of its interior or work area, to the location of the pump 23 and the reservoir 22. As a result, the hydraulic weight control and compensating apparatus A is not susceptible to damage or to breakage, particularly disruption of one of its hydraulic lines, which would result in the loss of pressure in the liquid 18 in the cylinder 1% and the dropping of the piston 13 in such manner that a buckling or column action could be imposed on the drill pipe M, possibly resulting in its failure.

The apparatus A disclosed automatically maintains the drilling weight on the drill bit R. By virtue of the pump 23 rotating at a desired speed, and because of the choke orifice 26, a substantially constant unit pressure of the liquid 18 in the cylinder results, this pressure acting over the effective area of the piston 13 and urging it upwardly, thereby relieving the drill string M and the mechanism S, H, T, L, E between the drill string and the piston rod 1-4 of a portion of the total weight hanging from the latter. With substantially constant pressure of the liquid 13, the weight on the drill bit R remains constant, despite lowering of the, drill string M as the result of the making of hole by the bit, the piston 13' merely moving downwardly in the cylinder. Assuming the floating barge C and derrick D do not move vertically, it is not even necessary for the driller to allow any line L to feed from the drawworks P for the purpose of lowering the drill string M as drilling proceeds, until the piston 13 is near the lower end 15 of the cylinder or the lower end of its stroke. When this occurs, a suitable amount of line L may be allowed to feed off the drawworks P, which will tend to reduce the tension in the line L extending between the crown block E and the traveling block T. Since the pressure of the liquid .is acting upwardly on the piston, any tendency for this line tension to reduce will immediately result in anupward movement of the piston 13 and the piston rod 14 in the cylinder 10*to prevent such reduction in tension, the piston and piston rod merely moving upwardly in the cylinder as additional line is fed from the drawworks until the piston 13 is adjacent to the upper end 11 of the cylinder, at which time the feeding of line from the drawworks P may be discontinued. The drill pipe M is rotated and the drilling action continues, the piston 13 and piston rod 14 again feeding downwardly as drilling proceeds, allowing the crown block E, lines L, traveling block T and swivel Sto travel downwardly with the string of drill pipe M and as the kelly K slides through the rotary table W,

until the piston 13 again nears the lower end of its stroke,

line can again be fed oil the drawtained constant, the u ward su ortin forceof the piston r l V e 1 on the drill pipe string M remains constant, resulting in a constant drilling weight being imposed'on the drill'bit R, forcing it against the bottom of the well bore B.

7 By virtue ofih e mechanism disclosed and described, the drilling weight on the bit can be maintained constant.

Such constant wei ht is'also maintained in'the event the V floating barge C and derrick D tend to move upwardly or downwardly as the result of the action of waves on the r the upward or downward movement of.

cylinder and of the drawworks.

body of water W in which the barge is floating. Assuming the floating barge and derrick were to rise as the result of wave action, the cylinder 10 will be carried upwardly with the derrick, but the piston 13 will remain in essentially the same position with the liquid 18 remaining at substantially the same pressure, inasmuch as the liquid is merely forced through the outlet line 25 and the choke orifice 26 back to the reservoir 22. Similarly, assuming that the barge C descends as the result of wave action, the derrick D and cylinder 10 are carried downwardly with it, effectively increasing the cylinder volume below the piston 13. However, the pump maintains the cylinder filled below the piston as its volume is increasing and produces substantially the same liquid pressure.

' Thus, during upward and downward movement of the floating barge C, derrick D and cylinder 1%), the piston 13 and piston rod 14 and the mechanism suspended from the rod 14 remains in substantially its same position, the cylinder 10 merely telescoping upwardly and downwardly along the pistons. The length of the cylinder is chosen such that the floating barge C and derrick D can rise and fall well beyond the maximum distance resulting from the action of waves without the piston engaging either the lower cylinder head 15 or the upper cylinder head 11. The cylinder 10 is always free to telescope or slide along the piston 13. During the up and down, or undulating, movements of the floating barge, derrick and cylinder, the piston 13 can still shift downwardly as the drill bit R increases the'depth of the well bore B.

During the upward and downward movement of the floating barge, derrick and'cylinder, as the result of water wave action, the fact that the drawworks P is connected to the line L and will also move upwardly and downwardly with the floating barge C does not interfere with the automatic compensating action of the hydraulic piston and cylinder mechanism. The piston 13 is always exerting a constant upward force on the lines L between the crown block E and the traveling block T and will malntain this constant force regardless of the movement to maintain a constant tension in the lines L. In effect,

as the drawworks moves up simultaneously with the rise of the floating barge, derrick and cylinder, the piston 13 follows this upward movement to a fractional extent to maintain the tension in the lines L constant.

Similarly, assuming the barge to move downwardly, which will carry the derrick, cylinder and drawworks-P downwardly with it, the descent of the drawworks relative to the crown block E would tend to increase the tension in the line L. Inasmuch as the unit pressure of the liquid 18 acting on the underside of the piston 13 is exerting a constant upward force on the latter, an increase in tension of the line results in immediate downward shifting of the piston 13 in the cylinder 10, forcing liquid from the cylin der and through the'choke orifice 26 back to the reservoir 22, the piston moving downwardly partially in the cylinder to maintain the tension in the lines L constant. Again the piston will move relatively downwardly in the cylinder to a fractional extent'of the downward movement of the The fractional follow-up of the piston 13 in the cylinder 10 is due to the fact that there are usually a substantial number of lengths of lines running between the crown block E and the traveling block T. Thus, if there are ten lines extending between the crown block and the traveling block, a feeding of a certain length ofline from or back onto the drawworks? will resultfin'a travel of #3 the crown block E with respect to the traveling block T of only one-tenth the amount of the feed irom or to the drawworks. Under the example given, the drawworks P actually is not rotating for the purpose of feeding line L from its drum (not shown) or feeding line back onto its drum, but it is the upward movement of the drawworks or its downward movement which is equivalent to allowing a line to pass over the crown block and traveling block, or a pulling line from the traveling block and crown block. In the example given of ten lines between the crown block and traveling block, for each unit of vertical movement of the drawworks P and of the floating barge C, derrick D and cylinder under wave action, the piston 13 would only follow up one-tenth of that distance within the cylinder 10 and would still maintain the tension in the line L constant, and, consequently, the weight on the drilling bit R constant.

Although the invention has been described with particular reference to a drill bit, it is applicable to maintaining a constant tension in any running-in string extending into the well bore, and even in maintaining tension constant in a wire line that might be extending into the well bore and connected to equipment therewithin. The maintenance of the liquid 18 in the cylinder at a constant unit pressure results in a constant upward force or tension on the piston rod 14 and or" the mechanism connected to its lower end, regardless of the upward or downward movement of the floating barge C, derrick D and the cylinder 10 with respect to the piston 13 and piston rod 14, and the mechanism suspended therefrom.

It is, accordingly, apparent that an apparatus has been provided which is capable of automatically maintaining the weight imposed by a drilling string M, or the like, constant, and for also automatically compensating for vertical movements of the mechanism mounted on the floating barge C. Upward and downward movement of the floating barge will not result in variations of the weight on the drill bit. Similarly, the same mechanism can be used for maintaining the weight or tension constant in any type of string, whether it be a tubular string or a wire line extending into the well here and supported from the rig.

I claim:

1. In apparatus for maintaining a substantially constant longitudinal stress in a running-in string disposed in a well bore which is supported by a rig including a derrick, a crown block at the upper portion of said derrick, and a suspension mechanism suspended from said crown block and to which the running-in string is operatively connected, the combination therewith of cylinder means and piston means slidable relatively in said cylinder means, a first of said means being secured to the upper portion of said derrick, and a second of said means being movable longitudinally along said first means and connected to said crown block, whereby said crown block moves longitudinally therewith, and means for maintaining fluid under pressure in said cylinder means and on said piston means as said piston means and cylinder means move longitudinally relative to each other, whereby at least a portion of the longitudinal stress in said running-in string is transferred from said crown block to said second means and through the fluid in said cylinder means to said first means and to said derrick.

2. In apparatus for maintaining a substantially constant longitudinal stress in a running-in string disposed in a well bore which is supported by a rig including a derrick and a suspension mechanism extending from the upper portion of said derrick and to which the running-in string is operatively connected, the combination therewith of cylinder means and pitson means slidable relatively in said cylinder means, a first of said means being fixedly secured to the upper portion of said derrick, and a second of said means being movable longitudinally along said first means and connected to said suspension mechanism,

whereby said suspension mechanism moves longitudinally therewith, and means for maintaining fluid under pressure in said cylinder means and on said piston means as said piston means and cylinder means move longitudinally relative to each other, whereby at least a portion of the longitudinal stress in said running-in string is transferred from said suspension mechanism to said second means and through the fluid in said cylinder means to said first means and to said derrick.

3. In apparatus for maintaining a substantially constant longitudinal tension in a running-in string disposed in a well bore which is supported by a rig including a derrick, a crown block at the upper portion of said derrick, and a suspension mechanism suspended from said crown block and to which the running-in string is operatively connected, the combination therewith of cylinder means secured to the upper portion of said derrick, piston means in said cylinder means and connected to said crown block, whereby said crown block moves longitudinally therewith, and means for maintaining fluid under pressure in said cylinder means for upward action on said piston means, whereby at least a portion of the longitudinal tension in said running-in string is transferred from said crown block to said piston means and through the fluid in said cylinder means to said cylinder means and to said derrick.

4. in apparatus for maintaining a substantially constant longitudinal tension in a runnin -in string disposed in a well bore which is supported by a rig including a derrick and a suspension mechanism at the upper portion of said derrick and to which the running-in string is operatively connected, the combination therewith of cylinder means fixedly secured to the upper portion of said derrick, piston means movable in said cylinder means and connected to said suspension mechanism, whereby said suspension echanism moves longitudinally therewith, and means for maintaining fluid under pressure in said cylinder means to exert an upward force on said piston means, whereby at least a portion of the longitudinal tension in said running-in string is transferred from said suspension mechanism to said piston means and through the fluid in said cylinder means to said cylinder means and to said derrick.

S. In apparatus for maintaining a substantially constant longitudinal stress in a running-in string disposed in a well bore which is supported by a rig including a derrick, a crown block at the upper portion of said derrick, and a suspension mechanism suspended from said crown block and to which the running-in string is operatively connected, the combination therewith of substantially vertical cylinder means and piston means slidable relatively in said cylinder means, a first of said means being secured to the upper portion of said derrick, and the second of said means being movable substantially vertically along said first means and connected to said crown block, whereby said crown block moves substantially vertically therewith, and means externally of said derrick for conducting fluid under pressure to said cylinder means and for maintaining said pressure in said cylinder means and on said piston means as said piston means and cylinder means move longitudinally relative to each other, whereby at least a portion of the longitudinal stress in said running-in string is transferred from said crown block to said second means and through the fluid in said cylinder means to said first means and to said derrick.

6. In apparatus for maintaining a substantially constant longitudinal stress in a running-in string disposed in a well bore which is supported by a rig including a derrick and a suspension mechanism extending from the upper portion of said derrick and to which the running-in string is operatively connected, the combination therewith oi substantially vertical cylinder means and piston means slidable relatively in said cylinder means, a first of said means being fixedly secured to the upper portion of said derrick, and the second of said means being movable substantially vertically along said one means and connected to said suspension mechanism, whereby said suspension mechanism moves substantially vertically therewith, and means externally of said derrick for conducting fluid under pressure .to said cylinder means for action on said piston means and for maintaining said fluid under pressure as said piston means and cylinder means move substantially vertically relative to each other, whereby at least a portion of the longitudinal stress in said runningin string is transferred from said suspension mechanism to said second means and through the fiuid in said cylinder means to said first means and to said derrick.

7. In apparatus for maintaining a substantially constant longitudinal stress in a running-in string disposed in a well bore which is'supported by a rig including a derrick, a crown block at the upper portion of said derrick, a traveling block below said crown block, a drawworks and a line extending from said drawworks and over said crown block and traveling block, said running-in string being operatively connected to said traveling block, the combination therewith of substantially vertical cylinder means and piston means slidable relatively in said cylinder means, a first of said means being fixedly secured to the upper portion of said derrick, and the second of said means being movable substantially vertically along said first means and connected to said crown block, whereby said crown block moves substantially verticallytherewith, and means for maintaining fluid under pressure in said cylinder means for action on said, piston means as 4 said piston'ineans and cylinder 'means move longitudinally' relative to each other, whereby at least a portion 5% of the longitudinal stress in said running-in string is transferred from said crown block to said second means and through the fluid in said cylinder means to said first means and to said derrick.

8. In apparatus for maintaining a substantially constant longitudinal tension in a running-in string disposed in a Well bore which is supported by a rig including a derrick, a crown block at the upper portion of said derrick, a traveling block below said crown block, a drawworks and a line extending from said drawworks and over said crown block and traveling block, said running-in string being operatively connected to said traveling block the combination therewith of substantially vertical cylinder means secured to the upper portion of said derrick, piston means slidable in said cylinder means and connected to said crowntblock whereby said crown block moves substantially vertically therewith, and means for maintaining fluid under pressure in said cylinder means for action upon said piston meansas said cylinder means and piston means move longitudinally relative to each other, whereby at least a portion of the longitudinal tension in said running-in string is transferred from said crown block to said piston means and through the fluid in said cylinder means to said cylinder means'and to said derrick.

References Cited in the file of this patent UNITED STATES PATENTS 2,187,392 Chappel Jan. 16, 1940 2,226,947 Sheldon Dec. 31, 1940 2,857,138 Svendsen et al Oct. 21, 1958 2,945,677 Kammerer July 19, 1960 

1. IN APPARATUS FOR MAINTAINING A SUBSTANTIALLY CONSTANT LONGITUDINAL STRESS IN A RUNNING-IN STRING DISPOSED IN A WELL BORE WHICH IS SUPPORTED BY A RIG INCLUDING A DERRICK, A CROWN BLOCK AT THE UPPER PORTION OF SAID DERRICK, AND A SUSPENSION MECHANISM SUSPENDED FROM SAID CROWN BLOCK AND TO WHICH THE RUNNING-IN STRING IS OPERATIVELY CONNECTED, THE COMBINATION THEREWITH OF CYLINDER MEANS AND PISTON MEANS SLIDABLE RELATIVELY IN SAID CYLINDER MEANS, A FIRST OF SAID MEANS BEING SECURED TO THE UPPER PORTION OF SAID DERRICK, AND A SECOND OF SAID MEANS BEING MOVABLE LONGITUDINALLY ALONG SAID FIRST MEANS AND CONNECTED TO SAID CROWN BLOCK, WHEREBY SAID CROWN BLOCK MOVES LONGITUDINALLY THEREWITH, AND MEANS FOR MAINTAINING FLUID UNDER PRESSURE IN SAID CYLINDER MEANS AND ON SAID PISTON MEANS AS SAID PISTON MEANS AND CYLINDER MEANS MOVE LONGITUDINALLY RELATIVE TO EACH OTHER, WHEREBY AT LEAST A PORTION OF THE LONGITUDINAL STRESS IN SAID RUNNING-IN STRING IS TRANSFERRED FROM SAID CROWN BLOCK TO SAID SECOND MEANS AND THROUGH THE FLUID IN SAID CYLINDER MEANS TO SAID FIRST MEANS AND TO SAID DERRICK. 